Modular welding system and method

ABSTRACT

A modular welding system for performing quick, easy and high quality welds. The modular welding system comprises a basic component system and a modular fixture component system. The basic component system provides the basic components which are needed to perform a quality weld efficiently. The modular fixture component system interfaces with the basic component system and provides a particular welding fixture assembly that performs a particular type of weld. More particularly, a stiffener type modular fixture component system and a butt/tee type modular fixture system are described. However, any other particular fixture type system may be integrated with the basic component system of the present invention.

[0001] This patent application is a continuation in part of provisionalpatent application No. 60/188,782 and is also a continuation in part ofpatent application Ser. No. 09/058,741.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention pertains generally to devices and methods formetal welding. More particularly, the invention is a modular weldingsystem and method which provides for quick, easy and accurate verticalwelds using a light weight, portable welding fixture.

[0004] 2. Description of the Background Art

[0005] When welding metal items together using arc or gas weldingtechniques, horizontal welding has traditionally been easier and lessexpensive to carry out than vertical welding. While welding metalsubstrates with conventional welding methods or plates together in ahorizontal position, gravity assists in keeping the molten weld puddlein place and facilitates the formation of high quality welds. Withvertical welding of metal substrates, the molten weld puddle is muchmore difficult to control, and the weld is correspondingly moreexpensive and time-consuming to perform. For this reason, structuralsteel fabricators go to great lengths to position metal substrates in ahorizontal relationship during welding and thereby avoid vertical welds.

[0006] The problems associated with making vertical welds areparticularly evident in the welding of “stiffener” plates into steel Ibeams or H columns for use in building construction. These stiffenersare used to transfer the moment load through a vertical column when ahorizontal column is welded to it. The welding of stiffeners intostructural beams is one of the most common welding operations andconsumes thousands of man-hours per year for a typical structural steelfabricator. The stiffener plates are welded to the web and flanges of acolumn in a position which is normal to the web and flanges of thecolumn. Thus, the weld connecting the stiffener plate to the web is at aright angle to the welds which join the stiffener plate to the flanges,and to complete all of the welds, the steel fabricator must eithercontinually reposition the heavy steel beam to maintain a horizontalposition for each weld, or must carry out difficult vertical welds.

[0007] Heretofore, the most common method of welding stiffeners intobeams or columns has been through use of conventional “flux-cored”welding wire methods. Flux-cored welding generally involves filling weldjoints with weld metal from a flux cored welding wire. The wire is madefrom a flat metal strip which is drawn into a hollow tube, filled with apowdered flux material, and rolled on a spool. During welding, the wireis unwound from the spool and fed through a flexible cable or conduit bya wire feeder device to a welding gun. When an operator presses thetrigger on the gun, the wire is fed out of the gun and strikes an arc onthe parent material to be welded. The arc energy melts the wire andparent material to form a homogeneous weld of fused wire and parentmaterial.

[0008] In order to properly weld stiffeners in place on columns usingflux-cored welding, the stiffener plate and weld joint must be properlyprepared so that the weld will meet the AWS (American Welding Society)code requirements. Generally, the stiffener is first cut from a standardpiece of mill plate and then bevel cut on three sides and ground cleanto remove any mill scale. Back-up bars, which retain molten metal inplace during welding, are then prepared for a fit-up operation whereinthe stiffener plate is carefully positioned relative to the column. Theperson carrying out the fit-up operation must weld the stiffener andbackup bars to the column such that a constant ⅜ inch gap is maintainedbetween the stiffener plate and the parent material of the column. Ifthe gap is too narrow, the stiffener must be ground until the proper gapis achieved. If the gap is too wide, the weld will require more metal(and thus more weld passes) to fill. Many welding or construction codesrequire that the backup bars be removed after the stiffener has beenwelded in place. Such removal is difficult and expensive, and generallyrequires gouging out the backup bars with a carbon arc, followed byadditional weld passes to fill in the gouged areas.

[0009] Small structural steel fabricators generally weld stiffeners intocolumns using flux-cored wire welding while the columns are horizontallypositioned between two upright supports, with the columns beingcontinually flipped or repositioned for each weld to avoid verticalwelding. Since the columns generally are very heavy, an overhead craneis used to lift the columns for repositioning. This process is very timeconsuming and expensive. Additionally, multiple weld passes are requiredto fill each weld joint, with thicker stiffener plates requiring moreweld passes. After each weld pass, the operator must stop and chip offthe slag covering the weld before the next weld pass. If any defectsoccur, the defect must be gouged out with a carbon arc and re-welded.

[0010] Larger structural steel fabricators sometimes use “pit welding”or “platform welding” for installing stiffeners, wherein columns arepositioned vertically so that all three sides of the weld joint are in ahorizontal or flat “hog-trough” position. Since the column is vertical,the stiffener is horizontal and the welds on all three sides are made inthe horizontal position. The stiffener is beveled on all three sides,and is cut so that a ⅜-inch gap is created between the stiffener and theinside of the column. When the operator welds the first weld pass, thisbackup bar retains the molten metal from falling through the gap, andprevents oxygen contamination of the molten puddle from the back side.This arrangement also allows a much larger puddle during welding, andrequires fewer weld passes to fill each weld joint. However, the backupbar must be removed in most application, requiring the operator toremove it after the joint has been filled. This is accomplished by arcgouging the backup bar from the back side of the stiffener and makingseveral weld passes to fill up the void caused by the arc gouging. Againthe removal of this backup bar is very time consuming and expensive. Theremoval of the backup bar requires that the beam be removed from the pitand welded horizontally; or that the beam be removed from the pit,turned upside down, returned to the pit and the backup bar removed andthe stiffener backside rewelded. Handling and positioning the verticallyoriented columns is difficult and requires an overhead crane and the useof a pit and/or platform, thus requiring a large amount of work space.Further, the location of the welding operation is generally not atground or floor level when using pit or platform welding techniques, andcan require the welding operator to be awkwardly or precariouslypositioned on a platform or ladder during the welding operation.

[0011] A vertical welding technique known as “electroslag” welding (ESW)has been developed to overcome the difficulties associated withrepositioning columns or other heavy substrates in order to permithorizontal welds. The electroslag method generally involves bringing theends of two vertically-oriented plates or substrates together such thata ¾ inch to one inch gap remains between the ends of the plates. Copperwelding shoes are then placed on each side of the gap to form a verticalchannel or cavity between the plates and welding shoes. This cavity isfilled with weld metal by placing a steel guide tube into the cavity tofeed welding wire into the channel. When the welding wire feeds out thebottom end of the guide tube, an arc is struck against the parentmaterial and a molten puddle is formed. A granular flux material issprinkled into the channel during welding, which melts to form aconductive slag. The arc is extinguished by the conductive slag, whichremains molten due to the resistance to the electric current passingbetween the welding wire and the substrates. Heat generated by theresistance of the molten slag melts the welding wire and fuses themolten metal to the substrates to form the weld. The welding wire iscontinually fed into the weld. The bottom of the guide tube is meltedoff by the heat of the molten flux puddle, and is therefore consumedinto the molten weld puddle. This process is called “consumable guide”electroslag welding. The guide tube can remain stationary during thewelding process, or can be oscillated from side to side. If the guidetube remains stationary, the width of the guide tube must match thethickness of the plates being welded. If the guide tube is oscillated, alarge variety of plate thicknesses can be welded with one size guidetube. If oscillation is used, the guide tube is oscillated orreciprocated within the cavity, and the cavity is filled with moltenmetal to join the plates together. The guide tube is consumable andcontributes to the weld metal. The copper shoes retain the weld puddlein place, and are removed when the weld is completed. The use of coppershoes eliminate the need for steel backup bars that must be removedafter welding—saving time and money. A comprehensive description ofelectroslag welding is provided in the American Welding Society WeldingHandbook, eighth edition, which is incorporated by reference.

[0012] While the electroslag process permits vertical welds, it haspreviously not met with much success due to the large amount of timerequired to set up prior to welding. Particularly, it is difficult andtime consuming to position and secure the copper shoes about the gapbetween the substrates that are to be welded. In the case of electroslagwelding of stiffeners onto columns, “L”-brackets generally must be cutand welded into place between the flanges and stiffener in order tosupport the copper shoes, with two L-brackets required for each weld.After the L-brackets are welded in place, steel wedges are pounded inplace between the L-brackets and copper shoes to hold the shoes inposition. When the weld is finished, the brackets must be removed.

[0013] Another drawback associated with conventional electroslag weldingis that that the guide tube must be carefully positioned within the gapto be welded, which requires careful alignment of the welding head andwelding oscillator mechanism. Incorrect alignment of the guide tube canresult in contact of the guide tube with tone of the copper shoes duringwelding, causing a 500 to 2000 Amp short, which will generally destroythe (expensive) copper welding shoe and interrupt the welding operation.Any such interruption of an electroslag weld operation is veryinconvenient, and expensive, and generally requires gouging out theincomplete weld and starting the entire operation over.

[0014] Still another drawback of conventional electroslag welding isthat the molten flux puddle in the weld cavity can cause the weldingwire to fuse to the bottom of the guide tube during welding, whichprevents wire from feeding into the weld. The welding then must beinterrupted, the copper shoes removed, and the weld area cleaned orground down to allow set up for a new weld start. As noted above, theinterruption of an electroslag weld in such a manner requires expensiveand time consuming cleanup of the incomplete weld followed by startingthe weld operation over again.

[0015] Welding controllers or control systems have been developed tofacilitate electroslag welding by controlling wire feed rate, weldingpower supply output, and oscillation, but such controllers generallybulky and heavy, and typically provide for only one type of weldcondition. If the weld condition varies during welding, defects mayoccur to the weld, or a catastrophic short against one of the copperwelding shoes may occur. For these reasons, electroslag welding ofstiffeners onto columns has not proved economical, and the weldingindustry has continued to use the flux-cored wire welding method.Further, previously known welding control systems have been based oncentralized control architectures having a star topology. These controlsystems are generally not scaleable or adaptable to changing needs ordifferent types of welding operations. Generally, the central processorboard for such systems must be re-designed and modified to meet newrequirements.

[0016] Accordingly, there is a need for a welding system and methodwhich overcomes the drawbacks presently associated with thecurrently-used flux-cored wire welding and electroslag welding methods,which eliminates the need for frequent re-positioning of heavy steelcolumns or other substrates during welding operations, which allowsquick and easy vertical welding with minimal set up time, which useslight weight, portable equipment, which prevents unwanted interruptionof welding operations, and which provides a distributed control systemto allow defect free welds under a variety of weld conditions. Thepresent invention satisfies these needs, as well as others, andgenerally overcomes the deficiencies of conventional electroslag weldingand flux-cored wire welding methods, and the drawbacks found generallyin the background art.

SUMMARY OF THE INVENTION

[0017] The present invention is a modular welding system which allowsquick and easy fabrication of high quality vertical welds under varyingconditions , reducing extensive set up time or use of heavy equipment.The modular welding system is comprised of two main groups, a basiccomponent system and a modular fixture component system. Preferably, allof the components associated with the basic component system are coupledto an articulated boom. Each of the modular fixture systems is suspendedfrom the end of the articulated. Each modular fixture component systemhas a particular fixture assembly that performs a particular type ofweld, yet can still interface with the same basic component system.

[0018] By way of example and not of limitation, the welding systemincludes two different modular fixture component systems, namely, aheavy duty butt/tee welding fixture and a stiffener welding fixture. Theheavy duty butt/tee welding fixture is used for heavy plate butt weldand tee welds which are common to bridge building. The stiffener weldingfixture is used for a making stiffener-to-flange welds which is commonto structural steel fabrication and is a lighter fixture than thebutt/tee welding fixture.

[0019] Each of the modular fixture component systems can be operativelycoupled to the basic component system by attaching the selected modularfixture component system physically and electrically to the basiccomponent system.

[0020] More particularly, the basic component system includes anarticulated boom assembly, an articulated boom lift, a wire feeder, astraightener, an articulated wire guide, a water circulator, anoperator's control module, a wire feed/straightener control module, anda welding power supply control module.

[0021] The butt/tee welding fixture component includes a butt/teefixture frame, an oscillator slide, an oscillator control module, aplurality of manual slides, a holding arm for a weld torch assembly, awelding torch rotator, a plurality of welding shoes, a butt/tee weldingtorch, and a plurality of wire feed conduits.

[0022] The stiffener welding fixture component includes a stiffenerfixture frame, a motorized oscillator slide, an oscillator controlmodule, at least one manual slide, a holding arm for a weld torchassembly, a welding torch rotator, a plurality of welding shoes, astiffener welding torch, and a plurality of wire feed conduits.

[0023] By way of example, during an electroslag welding process“consumables” are used to join parent materials with welding materials.By way of example and not of limitation, the consumables used in anelectroslag process may include welding wire, flux, and a consumableguide tube. Preferably, a welding wire comprising metal cored wire isused. During electroslag welding, it is preferable that a low moisturewelding flux be used. The consumable guide tube can be manufactured invarious sizes to fit a variety of applications and generally includesingle wire guide tubes, two wire guide tubes, three wire guide tubes,and four wire guide tubes.

[0024] In operation, a welding program is submitted to the operator'scontrol module by an operator. The welding program is input by anoperator of the welding system, however, the welding program may begenerated off-site by another third party. The operator's control moduleis the operator's input to program the welding operation. However, sincemost welding operators are not adept and computer programming, thecontrol panel has been designed to look like a standard analog controlpanel—which most welding operator's are familiar with. When the operatorenters variables into the operator's control panel, he uses pushbuttons, paddle switches, rocker switches, and control knobs. He feelscomfortable and competent in programming the panel in this way, becausethis is the way he has been trained to use existing competitive analogsystems. The operator's control panel, however, is a digital computer.When the operator pushes a button, or turns a know, he is programmingthe computer. The programming operation is completely transparent to theoperator. After the welding variables have been entered into the panelby the operator, the control module communicates the welding program toa wire feed/straightener control module, a power supply control moduleand a oscillation control module. The wire feed/straightener controlmodule controls the wire feed speed from the wire feeder and the wirestraightener. The power supply module controls the power supply. Theoperator control module, wire feed/straightener, and the power supplymodule are part of the basic component system. An oscillation controlmodule resident on the modular fixture component module controls theoscillation of the oscillation slide which oscillates the weld torch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be more fully understood by reference to thefollowing drawings which are for illustrative purposes only.

[0026]FIG. 1 is a perspective view of a welding system having astiffener welding fixture.

[0027]FIG. 2a is a perspective view of the articulated boom assembly.

[0028]FIG. 2b is a perspective view of the articulated boom assemblyshowing how the boom assembly is assembled.

[0029]FIG. 3a is a perspective view of the articulated boom lift.

[0030]FIG. 3b is a view of the top and bottom of the articulated boomlift and provides a more detailed view of the vertical carriage and thecarriage track plate.

[0031]FIG. 3c is a perspective view of the vertical carriage.

[0032]FIG. 4a is a perspective view of a wire feeder.

[0033]FIG. 4b is a perspective view showing the assembly of the wirefeeder.

[0034]FIG. 4c shows how forces are applied to the welding wire in thewire feeder.

[0035]FIG. 4d is a detailed view of the shaft encoder and roll arm ofthe wire feeder.

[0036]FIG. 5a is a perspective view of the wire straightener.

[0037]FIG. 5b is a perspective view showing the assembly of the wirestraightener.

[0038]FIG. 6a is a perspective view of the articulated wire guide.

[0039]FIG. 6b is a view of the showing the assembly of the articulatedwire guide.

[0040]FIG. 7a is a perspective view of the stiffener fixture module.

[0041]FIG. 7b is a view showing the assembly of the stiffener fixturemodule.

[0042]FIG. 8 is a perspective view of the weld shoes.

[0043]FIG. 9a is a perspective view of an oscillator slide.

[0044]FIG. 9b is a perspective view which shows the assembly of theoscillator slide.

[0045]FIG. 10a is a perspective view of the stiffener fixture weldtorch.

[0046]FIG. 10b is a perspective view of the assembly of the stiffenerfixture weld torch.

[0047]FIG. 11a is a perspective view of a manual adjusting slide for thestiffener fixture.

[0048]FIG. 11b is a perspective view showing the assembly of the manualadjusting slide for the stiffener fixture.

[0049]FIG. 12a is a perspective view of a weld torch rotator.

[0050]FIG. 12b is a perspective view of the assembly of the weld torchrotator.

[0051]FIG. 13a is a perspective view of a guide tube using stiffenerweld shoes.

[0052]FIG. 13b is a perspective view of a variety of guide tubes.

[0053]FIG. 13c is a perspective view of a guide tube using butt/tee weldshoes.

[0054]FIG. 14a is a perspective view of a flux dispenser.

[0055]FIG. 14b is a perspective view of the assembly of the fluxdispenser.

[0056]FIG. 15 is a perspective view of a modular welding system having abutt/tee welding fixture.

[0057]FIG. 16a is a perspective view of the butt/tee fixture module.

[0058]FIG. 16b is a perspective view of the assembly of the butt/teefixture module.

[0059]FIG. 17 is a perspective view of the butt/tee weld shoes.

[0060]FIG. 18a is a perspective view of a butt/tee weld torch.

[0061]FIG. 18b is a perspective view of the assembly of the butt/teeweld torch.

[0062]FIG. 19a is a perspective view of the heavy duty manual slide.

[0063]FIG. 20 is the face of the operator's control panel.

[0064]FIG. 21 is a high level block diagram of the modules whichcommunicate with the operator's control panel.

DETAILED DESCRIPTION

[0065] Referring more specifically to the drawings, for illustrativepurposes the present invention is embodied in the system shown generallyin FIG. 1 through FIG. 21. It will be appreciated that the system mayvary as to configuration and as to details of the parts. The inventionis disclosed generally in terms of heavy plate welding which may beapplied to electroslag or electrogas welding. However, the invention maybe used in a large variety of welding applications which employ a basiccomponent system and a modular fixture component system, as will bereadily apparent to those skilled in the art.

[0066]FIG. 1 is a perspective view of a welding system having astiffener welding fixture. The welding system 5 includes a basiccomponent system 10 and a modular fixture component system 12 which is astiffener welding fixture 14. The basic component system 10 includes anarticulated boom assembly 16, an articulated boom lift 18, a wire feeder20, a motorized wire straightener 22, an articulated wire guide 24, awater circulator (not shown), an operator's control module 26, a wirefeed/straightner control module 30, a welding power supply controlmodule 34, control cable assemblies, power cable assemblies, watercooling hoses, and air hoses.

[0067] The basic component system receives power from a power supply 36and welding wire from welding wire drums 38.

[0068] The modular fixture component system 12 is a stiffener weldingfixture 14 and is described in further detail in FIG. 7a. However, forpurposes of providing an overview of the stiffener welding fixture 14,the fixture 14 includes a stiffener fixture frame, a motorizedoscillator slide, an oscillator motor control module, a manual slide, aholding arm for a weld torch assembly, a welding torch rotator, aplurality of welding shoes, a stiffener welding torch, and a pluralityof wire feed conduits.

[0069]FIG. 2a is a perspective view of the articulated boom assembly 16.The articulated boom assembly 16 carries the weight of the wire feeder20, wire straightener 22, cable and hose assemblies 40 and thecounterbalance arm 42 which holds the weight of the modular fixturecomponent system 12. The arm articulation has pivot points 44 and 46comprising swivel pins. The pivot points 44 and 46 allow the weldingoperator to quickly position the welding fixture with ease.

[0070]FIG. 2b is a perspective view of the articulated boom assemblyshowing how the articulated boom is assembled. The articulated boomassembly 16 is made in two sections in which the primary section 48 is 8to 10 feet long and the secondary section 50 is 8 to 10 feet long.Preferably, each section of the boom is powder coated with a heavyplastic insulation to protect against accidental shorting of the weldingwire. The primary section 48 is mounted to a vertical surface capable ofcarrying the load. A boom mounting plate 52 is attached to a mountingsurface 54 with four bolts. The mounting plate 52 has trimmingadjustments to keep the boom level. Adjustable drag brakes have beendesigned into each pivot point 44 and 46 so the operator can adjust theforce require to position the boom 16.

[0071] An insulated plate 56 is located on either side of the boom 16 atthe mounting surface 54 end. This plate 56 contains a series of U-grooveroller guides 58 which provide a path for the welding wire to follow asit is pulled from the welding wire drums to the top of the weld boom.These roller-guides 60 allow a welding wire to be pulled around a curvewith a minimum of force. The roller-guide assembly is electricallyisolated from the boom for extra protection against shorting.

[0072] A plurality of fiberglass troughs 62 a, 62 b, and 62 c aremounted on the bottom of the boom 16 to provide a path for the cable andwater assemblies 40 which include power cables, control cables, waterhoses, and air hoses. The cable and water assemblies 40 enter the troughat the boom mounting surface 54 and leave at the wire feeder 20 toattach to the modular fixture component system 12.

[0073] A round pipe 64 with a 90-degree bend is mounted on the outer endof the boom 16. The horizontal section of this pipe has a pneumaticcylinder 66 inside. A cable 67 is attached to a cylinder arm 68, andtravels from the end of the pneumatic cylinder arm 68, over a pulley 70,and down to the modular fixture component system 12. Air pressure issupplied to the pneumatic cylinder until the pressure equals the weightof the modular fixture component system 12 and the fixture is inbalance. The welding operator can raise and lower the modular fixturecomponent system 12 with a minimum of effort.

[0074] The welding fixture is capable of making welds requiring up to2000 Amps. This high amperage requires six 4/0 cables. A tall weldrequires walking or leapfrogging the copper shoes up the weld. Fourshoes need four water input water hoses and four output hoses. Thearticulated boom assembly 16 is designed to allow the welding operatorto quickly move from one weld to the next without having the drag theseheavy cables all over the place.

[0075]FIG. 3a is a perspective view of the articulated boom lift 18.Referring to FIG. 3a and FIG. 2a, the articulated boom lift 18 isdesigned to adjust the position of the articulated boom 16 to theoptimal position for welding structures of varying height. Additionally,the articulated boom lift 18 makes it easier for the welding operator toposition the boom at floor level for reloading wire into the wirestraightener 22, wire feeder 20 and wire feed conduits. The articulatedboom lift 18 includes a vertical carriage 80 and a carriage track plate82.

[0076]FIG. 3b is a view of the top and bottom of the articulated boomlift 18 and provides a more detailed view of the vertical carriage 80and the carriage track plate 82. An AC gear motor 84 having a gearbox 86turns a long screw 88 which is fixedly coupled to the carriage trackplate 82. Preferably the gearbox 86 has a ratio of 5:1, the long screw88 pitch is 4-pitch, the AC gear motor is a 1HP motor. Preferably, thevertical carriage 80 travels at a speed of approximately 6 to 7 feet perminute and has a lifting capacity of approximately 2000 pounds.

[0077]FIG. 3c is a perspective view of the vertical carriage 80.Preferably, the vertical carriage 80 has plurality of cam followersbearings 90 which ride on the vertical carriage 80. Preferably each camfollower bearing 90 has a load capacity of 10,000 pounds.

[0078]FIG. 4a is a perspective view of wire feeder 20. Preferably, thewire feeder 20 comprises a variable motor 100 such as a ½ HP 2500 RPMvariable motor. A gear reducer 102 has a 30:1 reduction which produces awire feed speed range from 0-450 inches per minute (IPM). In itspreferred embodiment, the welding process uses a multi-wire process, andthe feeder is capable of feeding four wires with diameters from 0.035″to {fraction (3/16)}″ through couplings 104 a, 104 b, 104 c, and 104 d.The gearbox 102 includes a hollow-shaft reducer which allows the user toreplace the shaft if it becomes damaged.

[0079] Prior art wire feeders which have the capacity of feeding twowires at the same time use a single pressure roll to force the pluralityof wires into a double v-groove drive roll. As more pressure is applied,a greater load is transferred to the gearbox and the drive motor whichcan cause the drive motor to overheat. If too much pressure is applied,the shaft will deflect, resulting in unequal pressure applied to the twowires. Unequal pressure can cause the two wires to feed at differentrates, making the welding condition unstable, resulting in a welddefect.

[0080]FIG. 4b is a perspective view showing the assembly of wire feeder20. A shaft 106 which extends beyond the width of the gear reducer 102is configured to receive a plurality of drive rolls. Each of theplurality of drive rolls includes two serrated V-groove drive roll 108 aand 108 b joined by a steel keyway 110. The two serrated V-groove driverolls 108 a and 108 b are configured to receive a welding wire. Apressure roll arm 112 applies a downward pressure to the serratedV-groove drive rolls 108 a and 108 b. A more detailed view of the shaftencoder 120 and the roll arm 112 is shown in FIG. 4d. An idler roll arm114 applies an upward pressure to the serrated V-groove drive rolls 108a and 108 b. A spring 116 is used to apply pressure to both the roll arm112 and the idler roll arm 114.

[0081]FIG. 4c shows how forces are applied to the welding wire in thewire feeder. Referring to FIG. 4c as well as FIG. 4b, there is shownthat as the shaft 106 turns, the spring 116 applies a downward pressureto the roll arm 112 and wire 118 and an upward pressure to the idlerroll arm 114, thereby overcoming the prior art limitation of unequalpressure applied to the drive rollers. Preferably, the wire feederincludes four sets of drive rolls, pressure roll arms, idler roll arms,and springs as shown in FIG. 4a and FIG. 4b.

[0082] Referring back to FIG. 4b, it shall be appreciated by thoseskilled in the art having the benefit of this disclosure that if thewire feed rate is zero, the combination of drive rolls 108 a and 108 bmay continue to turn due to the motor 100 even if no wire is being fed.However, idler roll attached to the roll arm 112 only moves when thewelding wire 118 feed rate is greater than zero. The idler roll is onlyturned by the motion of the welding wire, not the motion of the driveroll. In this way, the speed of the wire is measured, not the speed ofthe drive roll. Therefore, the wire feed speed is more accuratelymeasured by monitoring the revolutions of the roll arm 112 with a shaftencoder 120 situated up against the outer race of the roll arm 112 thanby measuring the drive rolls revolutions. If the welding wire shouldslip on the drive rolls, the control system can accommodate for theslippage by feeding more power to the motor 100 and simultaneously turnoff the wire straightener 22 to prevent breakage of the welding wire.

[0083]FIG. 5a is a perspective view of the wire straightener 22. Thewire straightener 22 removes cast and helix from both the solid andmetal cored wires. Preferably, each wire straightener handles two wiresup to ⅛ inch in diameter. It shall be appreciated by those skilled inthe art that straight wire is critical element of performing a highquality weld.

[0084] By way of example, if wire casts toward one edge of a weldpuddle, a temperature gradient may be generated in the weld puddle whichwould result in incomplete fusion on one of the joint edges.Additionally, unequal base metal dilution can become so severe that itcan lower toughness in the heat affected zone (HAZ) of the plate withthe higher dilution.

[0085]FIG. 5b is a perspective view of the assembly of the wirestraightener 22. It shall be appreciated by those skilled in the artthat a welding operation requiring four wires uses two wirestraighteners 22. However, for illustrative purposes the assembly of onewire straightener is herein provided. Preferably, the two rotors 122 aand 122 b which straighten wires are driven by a ¼ HP, variable speed,DC motor 124, located between the rotors. The DC motor 124 has a doublelength gear-belt pulley 126 attached to a motor output shaft 128. Afirst gear belt 130 and second gear belt 132 are each coupled to thegear-belt pulley 126. The first gear belt 132 drives the right rotor 134and the second gear belt 130 drives the left rotor 136.

[0086] Welding wire is pulled from a drum through rotors 122 a and 122 bof the wire straightener 22. The welding wire which passes through eachrotor has both cast and helix. Helix in the wire continually changes thecast direction with regard to the rotor. In operation each rotorcontinually rotates around the wire and it counter-bends the cast, nomatter which direction helix in the wire places the cast. In this way,each rotor removes both cast and helix from the wire.

[0087] The wire straightener motor 124 receives speed commands from a 90VDC motor control module which is described in further detail below. Thespeed of the wire straightener motor 134 is determined by the speed ofthe wire feed motor 100 of FIG. 4a which is also controlled by the 90VDC motor control module. As the wire feed motor 100 speeds up, thestraightener motor 124 speeds up and conversely as the wire feed motor100 slows down, the wire straightener motor 124 also slows down.

[0088] In operation, the welding wire is threaded through each rotor 122a and 122 b. Each rotor has three U-groove bearings-one on either end,and one in the center (not shown). All three bearings are in line andallow the welding wire to pass through the center of each rotor 122 aand 122 b. To straighten the wire, the center bearing must be adjustedout of line with the end bearings. In this way each time the rotorturns; the out-of-line center bearing bumps the welding wire as itpasses through the rotor. Each bump counter bends the cast of the wireand straightens it, one bump at a time. A more detailed description ofthe wire straightener 22 is provided in patent application Ser. No.09/058,741 which is hereby incorporated by reference.

[0089] Preferably, the wire straightener motor 124 turns each rotor 122a and 122 b at speeds from 0 to 1750 RPM which depends on the feed rateof the welding wire. As the wire feeder 20 pulls wire through each rotor122 a and 122 b, the welding wire is straightened one bump at a time.The speed of each rotor is programmed to match the wire feed speed. Byway of example and not of limitation, if the wire is bumped every ⅛ inchat low wire feed speeds, it will also be bumped every ⅛ inch at highfeed speeds.

[0090]FIG. 6a is a perspective view of the articulated wire guide 24.The articulated wire guide 24 prevents the problems associated withpulling wire around sharp bends or curves. The articulated wire guide 24is designed like links in a chain wherein each link is identical to thenext. The links are designed so that each link may swivel +/−3 degreesor less. The total degree of link swivel determines the overall radiusof the wire guide arc. By limiting the total degree of link swivel, theradius along which the welding wire is pulled can be limited. Dependingon the application, links can be added and/or subtracted from thestandard length of 11 links to generate the appropriate radius for thewire guide arc.

[0091]FIG. 6b is a perspective view of the assembly of the articulatedwire guide 24. The articulated wire guide 24 includes a plurality offixed coupling segements which comprises a plurality of “links” in whicheach link includes a top U-groove roll plate 140 fixedly coupled to afirst bottom shoulder plate 142 with two screws 144 a and 144 b. Each ofthe two screws 144 a and 144 b are also used to couple two U-groovebearings 146 a and 146 b, respectively, to the U-groove roll plate 140.Each of the U-groove bearings 146 a and 146 b are adjacent to oneanother such that a welding wire cavity is defined by the U-groovebearings 146 a and 146 b which receives a welding wire. The articulatedwire guide 24 includes a plurality of movable coupling segments whichinclude another screw 146 movably couples a second bottom shoulder 150to the top U-groove roll plate 140, thereby allowing the swivel of +/−3degrees or less. The second bottom shoulder plate 150 is fixedly coupledto a second top U-groove roll plate 152 using two screws as previouslydescribed. The second U-groove roll plate 152 is then movably coupled tothe following bottom shoulder plate. The articulated wire guide 24 callsfor a plurality of fixed coupling segments and movable coupling segmentsto generate the so called links in the articulated wire guide 24. Thearticulated wire guide 24 sits on a round swivel mounting post 154 whichis fixedly coupled to a swivel mounting bracket 156 which insulated fromand coupled to the articulated boom 16.

[0092]FIG. 7a is a perspective view of the stiffener fixture module. Thestiffener welding fixture 14 reduces setup time for vertical welding.The fixture is designed to quickly locate the consumable guide tube inthe center of weld, and at the same time, clamp the copper shoes oneither side of the weld cavity.

[0093]FIG. 7b is a view showing the assembly of the stiffener weldingfixture 14. An oscillator slide 160 is mounted in the center of thevertical upright bracket 162. The oscillator slide 160 providesoscillation control of the guide tube 161 in the y-axis and is describedin further detail in FIG. 9. An oscillator control module 163 acts as acontrol module which powers and controls the oscillator slide 161. Amanual slide 164 is mounted on the front of oscillation slide 160. Themanual slide 164 provides control for placement of the guide tube 161 inthe z-axis. A more detailed description of the manual slide 164 isprovided in FIG. 11a and 11 b. A weld torch rotator 166 is mounted onthe front of the manual slide 164 and provides fine tune rotationalcontrol of the guide tube 161 about the x-axis. A more detaileddescription of the weld torch rotator is provided in FIG. 12a and 12 b.The weld torch rotator 166 includes a pair of precision ground rods 168a and 168 b which receive a weld torch 170. The weld torch 170 positionis determined by sliding the weld torch 170 back and forth on theprecision-ground rods 168 a and 168 b, thereby providing control alongthe x-axis for the placement of the guide tube 161. A more detaileddescription of the weld torch is provided in FIG. 10a and 10 b. Theconsumable guide tube 161 is mounted onto the bottom of the weld torch170. A pair of weld shoes 172 a and 172 b are used to define a weldcavity. Each of the weld shoes 172 a and 172 b is mounted onto analuminum arm 174 a and 174 b, respectively, and is driven by a righthand/left hand screw 176. When the operator turns the hand wheel of handscrew 176, the hand screw 176 causes the weld shoes 172 a and 172 b tomove toward the center point of the fixture 14. When the weld shoes comein contact with a stiffener (not shown), the center of the consumableguide tube 161 is forced to the center of the weld cavity.

[0094] In operation, after the weld shoes 172 a and 172 b have come incontact with the stiffener (not shown), the operator tightens twoclamping knobs 178 a and 178 b located on the front of the stiffenerfixture 14. This action forces the weld shoes 172 a and 172 b againstthe inside surface of the flange plate (not shown). It also centers theconsumable guide tube 161 in the weld gap. The guide tube 161 is now inposition to start the weld.

[0095] By way of example, if the guide tube 161 is 1-inch wide and thestiffener is 1-inch wide then oscillation is not necessary. However, ifthe stiffener plate (not shown) is thicker than 1-inch, the operator canoscillate the guide tube 161 to spread the weld puddle to occupy theweld cavity. The oscillation action of the guide tube 161 allows theoperator to weld stiffeners from 1 to 4 inches thick with the same guidetube 161 by increasing the width of oscillation to match the thicknessof the stiffener.

[0096] Referring to FIG. 8 there is shown a perspective view of the weldshoes 172 a and 172 b. The weld shoes 172 a and 172 b are also referredto as tee weld shoes 172 a and 172 b. Preferably, the tee weld shoes arewater-cooled copper welding shoes which keep the molten weld metal andflux bath contained in the weld cavity. Water circulates through theshoes at a flow rate of approximately 2 gallons per minute. This flowrate keeps the copper shoes from melting from excessive heat. Inconsumable-guide welding, the shoes do not move. For longer joints theshoes are repositioned in a leap frog manner, as welding continuesupward.

[0097] Preferably, the tee weld shoes 172 a and 172 b are cast from purecopper. Each shoe is cast in a sand mold with an interior passage forwater flow. A recess ⅛″ deep by 1″ wide is designed into the face ofeach shoe to shape the weld reinforcement. Chamfered edges are providedwhere the copper makes contact with the base material. These chamferededges help the molten weld metal to wet against the parent material toprovide a smooth transition between the weld metal and the parentmaterial. Each shoe has a ⅜″ NPT threaded hole on the input and outputfor connecting water circulation hose couplings.

[0098] Two 1-½″ square mounting pads 180 a and 180 b are cast into theback surface of each tee weld shoe. Each of these mounting pads 180 aand 180 b have four threaded holes for mounting. The four holes form a1″ square pattern and are drilled and tapped for 10-24 screws. The teeweld shoe is provided in 9″, 12″ and 18″ lengths. These lengths can beleapfrogged to make welds of various heights.

[0099] The tee weld shoes 172 a and 172 b are used in pairs on eitherside of the welding joint. When laced against the parent material,cooling water should always enter the copper shoes from the bottom andexit from the top. Water flowing from bottom to top reduces thepossibility of vapor-lock which could stop the flow of water.

[0100] Preferably, the 9″ long shoe is used with the stiffener fixturemodule 14. The square mounting pad 180 a matches the mounting holepattern on the fixture's movably aluminum arm 174 a (see FIG. 7b). Thetee weld shoes 172 a and 172 b can be positioned (mirror imaged) oneither side of the weld joint, so that the relief groove is alwaystoward the top of the Tee. After the tee weld shoes 172 a and 17 b havebeen attached to the stiffener fixture module 14, a radius can begrounded on the bottom of the tee weld shoe to match the radius of therolled beam where the web of the beam meets the flange.

[0101] When the tee weld shoe 172 a and 172 b is used with the butt/teewelder fixture (which is described in further detail below), a steel baris attached to the back of the shoe between the two mounting pads. Thisbar is necessary when using strong-backs and wedges to clamp the coppershoes against the weld joint. This bar helps eliminate damage to theshoe from the wedge, as it is forced between the shoe and thestrong-back.

[0102] Referring to FIG. 9a there is shown a perspective view of anoscillator slide 160 without the top cover. The oscillator slide 160 isa motorized box slide which is configured to carry a 10-lb load at theface and is designed to work in a dirty environment. All of themechanical components are housed in a dust-proof box 188. Preferably,either a manual slide 164 or a torch rotator 166 is mounted on thefaceplate 162 (see FIG. 7b).

[0103]FIG. 9b is a perspective view which shows the assembly of theoscillator slide 160. Only a faceplate 190 moves during the oscillationcycle. Inside the dust-proof cast aluminum box 188 is a pair ofprecision ground parallel shafts 192 a and 192 b. Slidably mounted oneach shaft 192 a and 192 b is a linear actuator slide block 194 a and194 b, respectively. At each end of the linear actuator 194 b is a groupof four canted bearings 196 which propel the linear actuator 194 b alongthe shaft 192 b as the shaft 192 b rotates. The canted bearings 196 arearranged so that they are 20 degrees to the tangent of the contact pointfor each bearing. The friction between the canted bearings 196 and theshaft 192 b causes the linear actuator slide block 194 b to move whenthe shaft 192 b is turned, just as a nut is forced to move when athreaded shaft is turned. The linear actuator 192 a operates in asimilar manner as linear actuator 192 b.

[0104] A drive motor 198 which is located between the two linearactuator slide blocks 194 a and 194 b and has a gear belt pulley 200mounted on the end of the drive motor 198 drive shaft. When the motorgear belt pulley 200 turns, a gear belt 202 transmits motion to two gearbelt pulleys 204 a and 204 b which are fixedly coupled to the precisionground drive shafts 192 a and 192 b, respectively. As the drive motor198 drive shaft turns, the two linear actuator slide blocks 194 a and194 b move in unison because they are both connected to the same gearbelt 202. The direction in which the linear actuator slide blocks 194 aand 194 b travel is determined by the direction of the drive motor 198.The advantage of this design is that it allows the linear actuator slideblocks 194 a and 194 b to slip on the shaft 192 a and 192 b,respectively, if the welding torch 170 runs into an obstruction while aweld is in progress. Additionally, the hardened and ground drive shafts192 a and 192 b reduces wear and allows the oscillator slide 160 tooperate in a very dirty environment.

[0105] The faceplate 190 is attached to the top face of the two linearactuator slide block 194 a and 194 b. As the drive motor 198 cyclesclockwise and counterclockwise, the face plate 190 oscillates back andforth. An encoder (not shown) is attached to the rear of the drive motor198. An oscillator control module (not shown) commands the drive motor198 to move, the encoder sends pulses back to the controller to count.There are a fixed number of pulses per linear inch of travel. Theoscillator control module counts these pulses to keep track of slideposition.

[0106] If the weld torch 170 of FIG. 7bruns into an obstruction,slippage between each of the canted bearings 196 contact points and theprecision-ground shafts 192 a and 192 b could accumulate into an errorfor the controller. To correct for this potential error, a linearsensing device is attached to the bottom of one of the linear actuators(not shown). If a slip occurs, the error is detected by comparing themotor encoder position (where the slide should be) with the linearsensing device (where the slide actually is).

[0107] It shall also be appreciated by those skilled in the art havingthe benefit of this disclosure that the size of the oscillator slide 160can be varied to carry greater loads or smaller loads. To minimize theweight of the modular fixture component system 12, the size and weightof the oscillator slide 160 should also be minimized.

[0108] For a more detailed description of the oscillator slide 160please see patent application Ser. No. 09/058,741 which is herebyincorporated by reference.

[0109] Referring to FIG. 10a there is shown a perspective view of thestiffener fixture weld torch 170. In one embodiment, the weld torch 170carries a two-wire consumable guide tube. Preferably, multiple wires areused instead of a single welding wire to generate a higher form factorwhich gives better mechanical properties to the weld.

[0110] Referring to FIG. 10b there is a perspective view of the weldtorch showing how it is assembled. In operation, the weld torch 170carries welding current of up to 1500 Amps from the power cables to theconsumable guide tube 161. The weld torch 170 is operatively coupled tothe oscillator slide 160, the manual slide 164 and the torch rotator166, and may be oscillated during the welding process.

[0111] The welding torch has four main components: an input power block210, a buss bar 212, an insulator plate 214, and a guide tube clampingplate 215. The input power block 210 contains two threaded holes toaccept welding wires. The input power block 210 is fixedly coupled tothe top of the buss bar 212 by four screws, and when the two pieces ofcopper are brought together, two holes form at the top of the joinedsections to receive the welding wires from the wire feeder 20.

[0112] An insulator plate 214 is made of a phenolic material and isattached to the front of the welding torch. Two grooves are milledinside the front insulator. These two grooves provide a path for thespring liners to carry welding wire to the consumable guide tube 161.The insulator plate 214 also provides electrical insulation between thewelding torch and the welding fixture. The insulator plate 214 has twoholes 216 a and 216 b, one on either side, to provide forward andreverse adjustment for the weld torch 170. Two precision ground rods 168a and 168 b (see FIG. 7b) are inserted into the two holes 216 a and 216b. The ground rods 168 a and 168 b are mounted on the torch rotator 166and provide a surface for the weld torch 170 to slip back and forth.When the weld torch 170 is in position, two locking screws 218 a and 218b hold it securely in place.

[0113] At the bottom of the buss bar 212 is a slot for receiving theguide tube 161. The top of the guide tube is placed in this slot so thatthe two holes in the guide tube lineup with the holes defined by thebuss bar 212 and the insulator plate 214. A straight wire path isprovided from the conduits, down spring liners (not shown), and into theconsumable guide tube 161. When the guide tube is in position, it isheld in place by the guide tube clamping plate 215. Screws 220 a and 220b are located on one side of the clamping plate 215 and providesufficient pressure when tightened to hold the guide tube 161.

[0114] Preferably, the welding torch is designed to accept a standardconsumable guide tube 161 which measure 1″ wide and is to carry two{fraction (3/32)}″ diameter metal cored wires at currents up to 1500Amps. The welding torch 170 and guide tube 161 combination is the mosteconomical for production welding and can be used to weld stiffenersfrom 1″ to 4″ thick.

[0115]FIG. 11a is a perspective view of a manual adjusting slide whichis designed for the relatively lightweight stiffener welding fixture 14.The manual adjusting slide is designed to overcome limitations in theprior art. Prior art “V-weigh” slides are subject to clogging andjamming from flux particles and smoke generated during the weldingprocess. Additionally, the V-weigh slides are difficult to adjust. Toovercome these limitations, the manual adjusting slide 164 is designedto travel along weighs which eliminates clogging and jamming.

[0116]FIG. 11b is a perspective view showing the assembly of the manualadjusting slide 164. The manual adjusting slide 164 includes a sixbearing slide block 229 which has three bearings on each side of the sixbearing slide block 229. As shown in FIG. 11b, one side of manualadjusting slide has three bearings 230 a, 230 b and 230 c. Although notshown, the other side has a similar configuration for the other threebearings. Each of the six bearings has a single contact point whichrides on four hardened, ground and round weighs 232 a, 232 b, 232 c, and232 d. Two of the weighs 232 b and 232 d are place in the bottom alongthe longitudinal seams of box 234. The six bearing slide block 229 isplaced on top of the two weighs 232 b and 232 d. An adjusting screw 236is threaded into the slide block 229 using a nut 238 located within acavity defined by slide block 229, wherein the cavity is in the centerof slide block 229. Two additional weighs 232 a and 232 c are placed inthe top of the top two longitudinal seams in box 234. The slide weighs232 a, 232 b, 232 c and 232 d are further protected by a sheet metaldust cover. When the slide block 229 moves back and forth, two stainlesssteel bands 238 a and 238 b help seal the interior components of theslide from outside contamination. Five setscrews 240 located on the sideof the box 234 are used to adjust the weighs 232 a, 232 b, 232 c, and232 d are used to eliminate any slop. Slop is generally defined as anyright/left play in a screw/nut system. Backlash is eliminated by the useof a lead screw nut 238, such as manufactured by Delrin-AF, located inthe center of the slide block 229. Backlash is generally defined as anyforward/backward play in a screw/nut system.

[0117]FIG. 12a is a perspective view of the weld torch rotator 166.Referring to FIG. 12a and FIG. 7b, the torch rotator 166 is used toalign the guide tube 161 within the sides of the weld joint to preventthe guide tube 161 from shorting against the welding shoes 172 a and 172b. The torch rotator is small, lightweight, yet rugged and durable.

[0118]FIG. 12b shows a perspective view of the torch rotator 166 havingthree main components which include a back mounting plate 250, arotating plate 252, and a front mounting plate 254. A rotator adjustingscrew 256 and a friction adjustment screw 258 are located on the backmounting plate 250.

[0119] The plastic rotating plate 252 rotates around an aluminum shaft260 machined into the back mounting plate 254. A round piece of brassrod 262 is slipped into a hole at the top of the rotating plate 252. Theside of the brass bar stock is drilled and tapped to accept theadjusting screw 256. A clamping knob 264 is attached to the end of theadjusting screw 256. When the clamping knob 264 turns the screw 256, thethreaded brass rod 262 is either pulled or pushed to move the rotatingplate 252. This configuration provides the operator with a fine rotatingadjustment for the consumable guide tube 161.

[0120] The back mounting plate 254 may be attached to any mountingsurface by four flat-head screws, placed through counter-sunk holes 266in the back mounting plate 254. After the back mounting plate has beenattached to a mounting surface, the plastic rotator plate is placed intothe back mounting plate and held in position by a washer 268. The frontmounting plate 254 is then attached to the rotator plate 252 with fourflat-head screws. The welding torch 170 is then attached to the frontmounting plate 254 with the rods 270 a and 270 b. When completelyassembled, the operator simply turns the adjusting screw 256 to rotatethe front mounting plate 254 and the weld torch 170.

[0121]FIG. 13a shows the perspective view of a consumable guide tubeused with stiffener weld shoes 172 a and 172 b. The guide tube ismanufactured with one, two, three or four grooves and FIG. 13a is of twowire guide tube. A single groove guide tube is used when welding withone wire. A two-grooved guide tube is used when welding with two wires,and so on. Each wire guide tubes can be manufactured with a variety ofwidths to the match the plate thickness being welded.

[0122] Button insulators 280 are attached to either side to the flatsurface of the guide tube. These button insulators are glued on to thesurface of the guide tube 161 with a high temperature alumina basedglue. The button insulators 280 are made from a flux which is used inthe electroslag welding process. The button insulators 280 are attachedto the guide tube 161 every 4 to 6 inches. When conducting anelectroslag weld, the molten flux puddle reaches the glued-on buttoninsulator and the insulator melts and becomes part of the molten fluxpuddle. The buttons are small enough that they cause no significantchange to the resistance, chemistry, or depth of the weld puddle.

[0123]FIG. 13b is side view of a variety guide tubes. Each of theconsumable guide tubes in FIG. 13b is made from two separate strips ofsteel in which the first strip 282 has at least one groove and thesecond strip 284 is flat. The two strips are made from steel which haveless than 0.10 Carbon and 0.10 Aluminum in the chemistry of the steel.The two strips 282 and 284 are then spot welded together to make theconsumable guide tube 161. When the flat strip is placed on top of thegrooved strip a ⅛ diameter hole is formed to provide sufficientclearance for a {fraction (3/32)}″ diameter welding wire to feed downthe groove.

[0124] Preferably, each of the strips 282 and 284 is between 22-guageand 10-guage in thickness. When welded together they form a guide tubethat is combined thickness of the two strips. . Referring also to FIG.13a, the button insulators 280 are approximately ¼″ thick and areattached to either side of the guide tube 161 producing a guide tubethickness of ⅝″ thick. For a narrow gap electroslag weld, this resultsin a ⅛″ clearance when placed inside the ¾″ wide narrow gap weld cavity.This clearance allows the guide tube to be oscillated to perform theweld. If the weld process requires that the guide tube be fixed in oneposition, rolled aluminum strips can be wedged on either side of theguide tube to eliminate the ⅛″ clearance.

[0125]FIG. 13c is a perspective view of a guide tube using the butt/teewelding shoes which are described in further detail below.

[0126]FIG. 14a is a perspective view of a flux dispenser. The fluxdispenser 290 is used if the welding system 5 is used for an electroslagprocess (see FIG. 1). The application of the electroslag process whichuses a consumable guide tube requires that initial quantities of flux beadded to the weld prior to activating cycle start. After cycle start hasbeen initiated, flux must be slowly added until the flux puddle reachesa depth of approximately 0.50″ to 1.5″. It shall be appreciated by thoseskilled in the art having the benefit of this disclosure that if steelbackup shoes are used, very little flux addition is required to finishthe electroslag weld. However, if water-cooled copper shoes are used, acertain amount of flux plates against the face of the copper during theelectroslag process. This flux must continually be replaced as the weldprogresses upward, so that a constant flux depth is maintained.

[0127] The flux dispenser 290 can be programmed by the operator controlpanel 26 to provide flux, as needed, for the entire welding operation.The flux dispenser program section in the control module has variablesthat can be filled-in so that the correct amount of flux is added at theproper time during the run of the weld. The operator must enter thewidth of the plate and the width of the gap between the two plates intothe control module. This information is necessary for the control moduleto calculate how much flux must be dumped prior to welding. After thearc is struck, an additional amount of preprogrammed flux will be addeduntil the arc goes out and the weld enters electroslag mode.

[0128] In operation, the flux from the flux dispenser 290 becomes amolten resistor that floats on top of the molten weld metal. During thewelding operation, if the flux becomes too shallow, the welding powersupply will become more unstable and experience greater swings inamperage and voltage. The amperage and voltage sensors will sense theseswings and turn the flux dispenser on, to add flux until the amperageand voltage swings settle down to acceptable limits. This action occursfor the entire weld.

[0129] Controlling flux depth is very important to the stability of theelectroslag process. If the flux puddle is too shallow, welding currentbecomes unstable and penetration into the parent metal decreases. Thiscondition can cause a lack of penetration to the parent metal, or fluxinclusions in the weld metal. If the flux is too deep, amperagedecreases, and the flux puddle becomes colder. This can result in a lackof penetration into the parent metal, and flux inclusions on the outeredges of the weld joint.

[0130] Referring to FIG. 14b there is shown a perspective view for theassembly of the flux dispenser 290. The flux dispenser is designed withdrop-tubes 292 a and 292 b. Electrically insulated tubes (not shown) arefixedly coupled to each of the drop tubes 292 a and 292 b so that fluxcan be dropped on either side of the consumable guide tube 161. Each ofthe drop tubes 292 a and 292 b are coupled to a main mounting block 294.The main mounting block 294 is configured to receive a gearbelt pulley296 and a small drive motor 298. The mounting block 294 also has anorifice 300 which receives flux from a beveled plate flux hopper 302.The beveled plate flux hopper 302 is confined by a second flux hopper304 which is preferably a plastic Lexan flux hopper.

[0131] In operation, as the consumable guide tube 161 oscillates to oneside, the motor 298 dispenses flux on the side opposite the guide tube161. Controlled flux addition eliminates the possibility of chilling themolten flux bath.

[0132]FIG. 15 is a perspective view of a modular fixture componentsystem having a butt/tee welding fixture frame. The welding system 310includes a basic component system 10 and a modular fixture componentsystem 12 which is a butt/tee welding fixture 312. The basic componentsystem 10 is the same as shown in FIG. 1 and includes an articulatedboom assembly 16, an articulated boom lift 18, a wire feeder 20, amotorized wire straightener 22, an articulated wire guide 24, a watercirculator (not shown), six 4/0 welding power cable assemblies, controlcable assemblies, water hose assemblies, air hose assemblies; and anoperator's control module 26, a wire feed control module 30, a dual wirestraightener control module 32, and a welding power supply controlmodule 34, which have all been previously described.

[0133] The modular fixture component system 12 is a butt/tee weldingfixture 312 is described in further detail in FIG. 16a and 16 b. Thebutt/tee welding fixture 312 includes a butt/tee fixture frame, amotorized oscillator slide, an oscillator motor control module, a manualhorizontal (forward/reverse) position trim slide, a vertical (up/down)position trim slide, a holding arm for a weld torch assembly, a weldingtorch rotator, a plurality of welding shoes, a stiffener welding torch,and a plurality of wire feed conduits which are described in furtherdetail below.

[0134]FIG. 16a is a perspective view of the butt/tee fixture module. Thebutt/tee fixture module reduces set-up time and increases control overthe welding process.

[0135] The butt/tee fixture module is designed to quickly locate theconsumable guide tube in the center of the weld cavity. The system canuse one to four welding wires at the same time, and provides for guidetube oscillation for large welds.

[0136]FIG. 16b is a view showing the assembly of the butt/tee fixturemodule 312.

[0137] A heavy-duty oscillator slide 314 is mounted on the center of thefixture's aluminum casing 316 to provide control of the guide tube 317.The heavy oscillator slide 314 is similar to the oscillator slide 160with the exception that the heavy-duty oscillator slide 314 is larger,preferably 8×8 than the oscillator slide 160, which is smaller,preferably 5×5. A heavy duty manual slide 318 is mounted directly on topof the oscillator slide 314. The heavy duty manual slide 318 providescontrol in the x-axis of the guide tube 317 and also allows a weldingtorch 320 to be trimmed in the forward and reverse directions. Thewelding oscillator center-line adjustment is used for right and leftwelding torch trim. A more detailed description of the heavy duty manualslide is provided below. An “L-bracket” casting 322 is mounted on top ofthe manual slide 318 and provides a horizontal mounting surface for anoscillator module 323 which is a control module which powers andcontrols the oscillator slide 314. Additionally, the L-shaped bracketprovides a vertical mounting surface for the torch rotator 324, thevertical manual slide 326 and horizontal manual slide 328. The torchrotator 324 provides the fine tune rotational control of the guide tube317 about the x-axis. The vertical manual slide 326 is coupled to thetorch rotator 324 and provides control of the guide tube along thez-axis. A horizontal manual slide 328 is coupled to the vertical manualslide 326 and provides for control of the guide tube along the y-axis.The horizontal manual slide 328 and vertical manual slide 326 aresimilar to the manual slide 164 in FIG. 11a and 11 b. The welding torch320 is mounted on the front of the horizontal manual slide 328. A moredetailed description of the welding torch 320 is provided below.

[0138] The weld torch 320 can receive one or more wires from the wirefeeder 20. The weld torch 320 is also designed to accept a one wire or amulti-wire consumable guide tube 317. Using oscillation, a two-wireguide tube system can weld plate up to 4 inches thick. A four-wire torchcan accept up to four wires from the wire feeder 20, and can accommodateone to four-wire guide tubes. A four-wire guide tube can weld plates upto 12 inches thick when used with oscillation.

[0139] The butt/tee welding fixture 312 is designed to hold both buttweld joints and tee weld joints. The butt/tee welding fixture 312 can bequickly clamped onto any plate for welding with a clamping assembly. Theclamping assembly comprises a front clamping device 330 a and a backclamping device 330 b. Each clamping device 330 a and 330 b iscontrolled by a lead screw hand wheel 332 a and 332 b, respectively,which is also part of the clamping assembly. The clamping assemblycenters the consumable guide tube by symmetrically clamping the butt/teeweld fixture 312 about the center of the weld.

[0140] The dual-wire guide tube is between 1-inch and 1-¼ inch wide. Ifthe butt weld or tee-weld guide tube is much wider than 1-inch/1-¼ inchthen the operator cant oscillate the guide tube to spread the weldpuddle. The oscillation action of the guide tube allows the operator toweld plates up to 4 inches thick with the 1-inch/1-¼ inch wide guidetube. This is accomplished by increasing the width of the oscillation tomatch the plate thickness.

[0141]FIG. 17 is a perspective view of the water-cooled butt-weld shoes.The butt weld shoes 340 a and 340 b are similar to the tee weld shoeswhich have been described previously. The butt weld shoes include tworelief grooves 342 a and 342 b which are cast into the back face of eachshoe. These relief grooves 342 a and 342 b are used to capture astainless channel that can be attached to the back of the shoe to reducewear caused by wedges forced against the back of the shoe. The butt-weldshoe is provided in a plurality of forms and lengths.

[0142] The butt-weld shoes are used in pairs on either side of thewelding joint. When placed against the parent material, cooling watershould always enter the copper shoe from the bottom and exit from thetop. Water flowing form the bottom to the top reduces the possibility ofvapor lock which could stop the flow of water.

[0143] Referring to FIG. 18a there is shown the butt/tee weld torch 320configured to carry two weld wires. The butt/tee weld torch 320 designis similar to the stiffener weld torch 170. However, the butt/tee weldtorch 320 does not have locking screws 218 a and 218 b (see FIG. 10b).Referring to FIG. 18b which is a view showing the assembly of thebutt/tee weld torch 320, an additional difference is noted. Namely, anadditional insulator plate is fixedly coupled to the buss bar 342, andmovably coupled to the (up/down) manual slide 328.

[0144] Referring to FIG. 19a there is shown a perspective view of theheavy duty manual slide 318. The heavy duty manual slide 318 is capableof carrying greater loads than the manual slide 164 in FIG. 11a and 11b.

[0145]FIG. 19b is a perspective view of the heavy duty manual slide 318.The heavy duty manual slide includes a slide block 350 which rides oneight cam follower bearings 352 wherein a pair of cam follower bearingsare disposed on each corner of the slide block 350 such that the pair ofcam followers are occupy the top and bottom of each corner of the slideblock 350. Each of these eight cam follower bearings 352 have oneassociated contact point that rides on weighs 354 a and 354 b. Each ofthe eight cam follower bearings 352 is disposed at an angle to the sideblock 350 side walls and are not orthogonal to the side block 350 sidewalls. The weighs 354 a and 354 b are further protected from dust andflux with sheet metal dust covers 356 a and 356 b. A dust cover 358 hastwo slots machined into the dust cover. The two slots receive two risers360 a and 360 b. When the slide block 350 slides back and forth, thesheet metal dust cover 356 a and 356 b seal the slots and protect thecomponents within the slide 318 from contamination.

[0146] The weighs 354 a and 354 b are placed in box 361 which has twolongitudinal slots machined into the sidewalls of the box 361 forreceiving the weighs 354 a and 354 b. The eight bearing slide block 350is placed between the weighs 354 a and 354 b. An adjusting screw isthreaded into a nut 364 which is located in the center of the slideblock 350. Preferably, the nut 364 is a Delrin-AF lubricated plasticnut. Five set screws 364 are located on the side of box 361 and are usedto adjust the weighs 354 a and 354 b to eliminate slop from the manualslide. Backlash is eliminated by using the nut 364.

[0147]FIG. 20 presents the face of the operator's control panel 26. Theoperator's control panel 26 is the central interface for the modularcontrol system. Additionally, the control panel 26 provides a simplifiedmethod of programming a welding process such as electroslag or anelectrogas welding process.

[0148] To enter a welding program into the control panel 26, theoperator enters the appropriate button to enter a program variable. Theoperator then toggles through six program screens and fills in the blankspaces by activating the appropriate knob, toggle, rocker or button. Byway of example and not of limitation, when setting a value for amperage,the operator uses an amperage control knob. When setting voltage, theoperator uses the voltage control knob. When all the blanks for each“screen” have been filled, the welding program is complete.

[0149] In operation, each module continually communicates with theoperator's control panel 26. In this way the operator's control module26 carries out the program entered into it by the welding operator. Toenter a welding program, the welding operator must first press the“program button” 350. A portion 352 of the program button 350 issubsequently lit indicating that the control panel is in program mode.The operator then uses the “cycle stop” button 354 to advance forward tothe next screen. He uses the “cycle start” button 356 to advancebackwards to the past program-input screen. When he arrives at eachscreen, he uses the appropriate knob or button to input programvariables into each one of the blank spaces in the program screen. Whenhe has filled in all six screens he presses the program button 350 whichbecomes unlit indicating that the panel is out of program mode and intowelding mode, and therefore ready for the welding process to begin. Amore detailed description of the operator's control panel is provided inpatent application Ser. No. 09/058,741 which is hereby incorporated byreference.

[0150]FIG. 21 shows a high level block diagram of the “modules” whichcommunicate with the operator's control panel 26. The welding program isprocessed by a CPU 360 resident on the operator's control panel 26. TheCPU then transfers the information to a 6-wire bus 362 whichcommunicates with an oscillation module 364, a wire feed/straighteningmodule 366 and a power supply module 368. It shall be appreciated bythose skilled in the art having the benefit of this disclosure that the6-wire bus 362 carries the information previously requiring 150 wires inan analog control system. Reducing the number of wires from 150 to 6,makes cabling and maintenance of the system much simpler.

[0151] The oscillation module 364 is a 24VDC control module which powersthe “oscillator units” that oscillated the welding torch back and forthduring the welding operation. The oscillator centerline adjustment alsopositions the weld torch for the stiffener fixture module 14 or thebutt/tee fixture 312. The oscillation module 364 is part of the modularfixture component system. The oscillation module 364 is similar to theoscillation control module 163 and oscillation control module 323previously described in FIG. b and FIG. 16b, respectively. An opticallyisolated H-bridge (not shown) provides up to 10 amps of motor drivepower at 24 volts, and uses a quadrature encoder to provide positioningcontrol to an accuracy of (+/−) 0.005 inches. Velocity ranges from 0.5inches per minute (IPM) to 50 IPM and is controlled to 0.1 IPM. Safetyfeatures include excessive-position error detection and thermal shutdowncontrol, with automatic recovery capability. Other on-board I/O includesoptically isolated inputs from an index position indicator and relaysfor control of flux feed or other external devices.

[0152] A more detailed description of the motor control module isprovided in patent application Ser. No. 09/058,741 which is herebyincorporated by reference.

[0153] The wire feed/straightening module 366 is comprised of a 90 VDCcontrol module which controls and powers the motors used for controllingwire straightening and wire feeding. An optically isolated H-bridgeprovides up to 10 amps of motor drive power at up to 130 volts and usesa quadrature encoder (not shown) to determine wire feed speed. Velocityranges from 0.5 inches per minute (IPM) to a maximum determined by thetype of wire feeder. Speed is controlled to 0.1 IPM. Safety featuresinclude the wire feed detection which allows the wire straightener toonly run when all wires are being fed by the wire feed/straighteningmodule 366. The 90 VDC motor control module also communicates with theoperator control module panel at least once a second, otherwise it willcease motion. Other on-board I/O includes three optically isolated inputand relay outputs for control of external devices.

[0154] In operation, the wire feed/straightening module 366 receivescommands from the operator control panel 26 over the 6-wire bus 362. Theoscillation module 364 provides local control of the wire feeder 20based on the commands input into the operator control panel 26. Thesecommands set wire feed speed in IPM and wire jog speed as a percent ofmotor output. The operator's control panel 26 does not directly controlthe wire staightener 22, rather it is controlled by the wire feed speedand the output of the wire feeder. The wire straightener 22 only runswhen wire is fed in the forward directions. Running the wire feeder inthe reverse direction can be performed for short lengths.

[0155] The wire feed/straightening module 366 uses a feed forwardalgorithm to control wire feed speed. This is because the controlledparameter is wire feed speed and no positioning logic is required. Wirefeed speed is used as the control parameter, rather that the weldingpower supply current output (amps) because the current output depends ona number of variable including wire feed speed. This also reduces theload on the 90 VDC motor control module since it does not need tomonitor network packets for data coming from the welding power supply.

[0156] Wire feed direction can be both forward and reverse, but during awelding cycle the direction is limited to the forward direction. Whenthe welding control section of the operator control module 26 is in themanual mode the operator can jog the wire in either direction toposition it for welding or for maintenance of the welding system. Wirejog velocity is stored as a separate value from wire feed speed and isbased on a percentage of the motor driver output.

[0157] Shaft encoders 120 are attached to each one of the four wire feeddrive rolls. See FIG. 4b. When the wire feed/straightening module 366 isused to control the motorized wire straightner 22, the module 366accepts inputs from the shaft encoders 120. If one of the encoders 120stops giving an output, the module 366 interprets this as wire stoppageand turns off the motorized wire straightener 22 to eliminate wirebreakage until the problem is fixed and wire feed is resumed.

[0158] The power supply module 368 is a welding power control modulewhich provides welding voltage control and feedback from the weldingpower supply 36. Outputs consist of a SPST relay and a digital to analog(DAC) converter. The DAC provides a 12 bit +/−12 V output supportingvarious control voltage requirements of different welding powersupplies.

[0159] Voltage and current generated by the welding power supply 36 arecommunicated to the operator control panel 26 with the power supplymodule 368. The power supply module 368 also includes a water flowdetection input. It shall be appreciated by those skilled in the arthaving the benefit of this disclosure that the DAC and analog inputcircuits are optically isolated from the logic and communicationssection of the board, as well as from each other to allows each sectionto float at a different voltage and keeps the EMI from the welding powersupply inputs form interfering with welding power supply control moduleoperation.

[0160] During a welding cycle the operator control panel 26 polls thewelding power supply module 368 for output levels of voltage andamperage. This information is used to monitor the weld cycle and isoutput to the operator control panel 26.

[0161] The operator control panel 26 also receives a set of flagsindicating the status for the welding power supply and the cooling watersystem. Cooling water is critical to the operation of the weld system,as the weld shoes, which act as a mold for the weld will melt if notcooled. The welding power supply module 368 is configured to either senda signal to the operator to fix the problem, or shutdown the weldingpower supply if the water fails, or can be configured to close thecontactor of the welding power supply 36 if there is no water flowduring a five-second period. The operator control panel 26 will notallow a welding cycle to start if there is no water flow and canshutdown a weld cycle upon notification by the welding power supplymodule 368. The operator is also informed of the problem on the operatorcontrol panel 26.

[0162] A more detailed description of the control system is provided inpatent application Ser. No. 09/058,741 which is hereby incorporated byreference.

[0163] Accordingly, it will be seen that this invention provides awelding system and method which allows quick and easy fabrication ofhigh quality vertical welds under varying conditions without requiringextensive set up time or use of heavy equipment, and which isparticularly effective at installing stiffener plates onto structuralbeams or columns. Although the above description contains manyspecificities, these should not be considered as limiting the scope ofthe invention but as merely providing illustrations of some of thepresently preferred embodiments of the invention. Thus, the scope ofthis invention should be determined by the appended claims and theirlegal equivalents.

What is claimed is:
 1. A modular welding system, comprising: (a) a basiccomponent system having an operator control module which controls apower supply and controls a wire feeder; and (b) a modular fixturecomponent system which interfaces with said basic component system, saidmodular fixture component system having a particular fixture assemblywhich performs a particular type of weld.
 2. The welding system of claim1, wherein said basic component system further comprises a power supplycontrol module which communicates inputs from said operator controlmodule to said power supply.
 3. The welding system of claim 2, whereinsaid basic component system further comprises a wire feeder controlmodule which communicates inputs from said operator control module tosaid wire feeder.
 4. The welding system of claim 3, wherein said basiccomponent system further comprises an articulated boom which isconfigured to receive said modular fixture component system.
 5. Thewelding system of claim 4, wherein said modular fixture component systemcomprises a weld torch which receives said at least one welding wirefrom said wire feeder.
 6. The welding system of claim 5, where saidmodular fixture component system comprises an oscillator slideconfigured to oscillate said weld torch.
 7. The welding system of claim6, wherein said modular fixture component system comprises an oscillatorcontrol module in communication with said operator control module, saidoscillator control module configured to control said oscillator slide.8. The welding system of claim 5 wherein said modular fixture componentsystem includes a stiffener fixture frame.
 9. The welding system ofclaim 5 wherein said modular fixture component system includes abutt/tee fixture frame.
 10. A modular welding system having a basiccomponent system which comprises: a boom configured to receive at leastone welding wire; a wire feeder coupled to said boom, said wire feederconfigured to transfer said at least one wire across said boom; and anoperator's control module configured to control said wire feeder. 11.The basic component system of claim 10 further comprising a wire feedcontrol module which receives wire feed signals from said operator'scontrol module and controls the communications of said wire feed signalsto said wire feeder.
 12. The basic component system of claim 11 furthercomprising a power supply control module which receives power supplysignals from said operator's control module and controls thecommunications of said power supply signals to a power supply.
 13. Thebasic component system of claim 12 further comprising a wirestraightener which straightens said at least one wire transferred bysaid wire feeder.
 14. A modular welding system having a modular fixturecomponent system, comprising: a weld torch configured to receive atleast one welding wire from a wire feeder, said weld torch alsoconfigured to receive a consumable guide tube which receives said atleast one wire, said weld torch configured to communicate powergenerated by a power supply to said guide tube; and an oscillator slideconfigured to oscillate said weld torch.
 15. The modular fixturecomponent system of claim 14 further comprising at least one manualslide to position said weld torch.
 16. The modular fixture componentsystem of claim 15 further comprising an oscillation control modulewhich controls said oscillator slide.
 17. The modular fixture componentsystem of claim 16 further comprising a weld torch rotator configured torotate said weld torch.
 18. The modular fixture component system ofclaim 17 further comprising two weld shoes which define a weld cavitywhich receives said guide tube.
 19. The modular fixture component systemof claim 18 having a stiffener fixture frame.
 20. The modular fixturecomponent system of claim 18 having a butt/tee fixture frame.